Calculation serial number entry
I'm creating a recipe database. I want to classify each entry by Menu Class (number) and serial number (auto-entry).
I have a value list with "Meat, Poultry, Seafood, etc" My thought was to create a calculation field to turn the prefix into a number (ie Meat = 01-, Poultry =02- and combine this with a serial number value. This seems pretty easy, I would like to have a Meat ID of 01-0001 and a Poultry ID of 02-0001. But I don't see that working. The next record, if Poultry would be 02-0002.
What I am having trouble with is with the calculation field which is IF the Category = "Meat" than "01-". It looks as if I can't change this number once entered. If I enter Category "Meat' and get a prefix of 01-, but realize this is actually a Poultry item. When I change from Meat to Poultry I want the prefix to change to 02-, but it remains the original entry of 01-